The invention concerns modified synthetic plastic materials, which are derived from elastomers as well as mixed- and copolymers thereof with thermoplastic properties and from liquification products from coal as well as, if desired, customary filler materials.
Synthetic plastic materials of this type are used principally for the manufacture of extrusion, injection and press forms. These are used in e.g. the construction and installation sector for sealing and protection purposes, for example as foils for sealing against water.
For such purposes a large number of synthetic plastic mixtures are known, which are principally comprised of ethylene-copolymerisates as plastic component and with known bitumina of a tar basis.
From U.S. Pat. No. 3,249,567 are known mixtures of about 4 to 95 weight-% aromatic asphalts from petroleum and about 5 to 95 weight-% ethylene-copolymerisates with a 10 to 40 weight-% portion of acrylic acid ester, calculated from the weight of the copolymerisates. Test samples from such mixtures achieve tear resistances up to about 4.5 N/mm.sup.2 and tear elongations up to about 900%.
From DE-AS No. 24 41 403 molded articles are known which are essentially ethylene-copolymerisates and bitumen, in which the bitumen is an extract and/or precipitate which according to German technical specification DIN 1995 has a penetration at 25.degree. C. which is smaller than 10. Test bodies of such mixtures have tear resistances up to about 8 N/mm.sup.2 and tear elongations up to about 1100%.
Building sheets are known from DE-PS No. 19 48 526, which are about 45 to 50 weight-% a mixture of polyethyleneacrylic acid ester copolymerisate and a small amount of bitumen, about 10 to 15 weight-% high-pressure polyethylene as well as about 40 weight-% anthracite dust with a grain size up to 30.mu. and up to 30 weight-% uncombustible residue, calculated from the anthracite dust component. Depending upon the preparative method, tear resistances between 2 and 5 N/mm.sup.2 and tear elongations between 300 and 1000% are achieved.
Finally, in the German application P 28 01 154.3 mixtures are described of 30 to 90 weight-% thermoplastic synthetic materials, in particular polyolefins and copolymers thereof as well as, if desired, up to 25 weight-% elastomers with thermoplastic properties, and of 20 to 60 weight-% of a product from the liquification of coal which boils above 350.degree. C. at normal pressure, as well as filler material, if desired. Tear resistances from 4 to 26 N/mm.sup.2 and tear elongations from 10 to 660% are achieved.
With this mixture of German application No. P 28 01 154.3 it is particularly important that all components from the liquefaction of coal with a boiling point at normal pressure below 350.degree. C. are removed before mixing with the synthetic plastic at an operating temperature between 150.degree. and 250.degree. C. Thus, the mixtures contain only high-melting residues from coal hydrogenation. In addition, the mixture with 30-90 weight-% calculated from the mixture has a high synthetic plastic component. The residue is here merely an extender for the synthetic plastic component.